The present invention relates to a running gear frame for a rail vehicle with a central transverse beam and two longitudinal beams connected together in a frame transverse direction via the transverse beam, wherein the transverse beam has at least a front web element, a rear web element and a transverse beam lower chord. The web elements run between the longitudinal beams in the frame transverse direction and a frame height direction and are connected therewith and are arranged spaced apart in a frame longitudinal direction at least by a web element distance. The transverse beam lower chord extends on an underside of the transverse beam between the longitudinal beams and is connected with the web elements. The invention furthermore concerns a running gear with a running gear frame according to the invention and a rail vehicle with a running gear according to the invention.
In modern rail vehicles which are operated at comparatively high nominal speeds, usually the problem occurs that at particular points in the vicinity of the running gear at which the air flow detaches from the vehicle components arranged there, flow conditions occur which at high speeds lead to a substantial increase in drag and considerable sound emissions. This is partly because downstream of the detachment point, a continuously widening shear layer is formed. The wider this shear layer expands, the greater the associated drag. Furthermore in this shear layer usually periodic pronounced vortices are formed (so-called Kelvin-Helmholtz instability) with associated sound emission.
If this shear layer hits running gear components such as for example the underside of a drive motor or a transverse beam of a running gear frame, further turbulence is induced which leads to an increase in drag and sound emissions.